Prevention of early-onset neonatal group B streptococcal disease with selective intrapartum chemoprophylaxis

N Engl J Med. 1986 Jun 26;314(26):1665-9. doi: 10.1056/NEJM198606263142603.


Most cases of neonatal group B streptococcal disease with early onset have an intrapartum pathogenesis. Attack rates are increased substantially in infants born to mothers with prenatal group B streptococcal colonization and various perinatal risk factors (premature labor, prolonged membrane rupture, or intrapartum fever). In a randomized controlled trial, we studied the effect of selective intrapartum prophylaxis with ampicillin in 160 such high-risk women. In infants born to mothers who received intravenous ampicillin during labor, as compared with controls who received no treatment, neonatal colonization with group B streptococci was present in 8 of 85 (9 percent) versus 40 of 79 (51 percent; P less than 0.001), colonization at multiple (greater than or equal to 3) sites was observed in 3 of 85 (4 percent) versus 24 of 79 (30 percent; P less than 0.001), and bacteremia occurred in none of 85 versus 5 of 79 (6 percent; P = 0.024). The side effects of ampicillin were limited to a single episode of urticaria in a mother who had no history of penicillin allergy. We conclude that intrapartum ampicillin prophylaxis in women with positive prenatal cultures for group B streptococci who have certain perinatal risk factors can prevent early-onset neonatal group B streptococcal disease.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Ampicillin / administration & dosage*
  • Clinical Trials as Topic
  • Female
  • Genital Diseases, Female / microbiology
  • Humans
  • Infant, Newborn
  • Labor, Obstetric
  • Pregnancy
  • Pregnancy Complications, Infectious / microbiology
  • Random Allocation
  • Rectum / microbiology
  • Risk
  • Streptococcal Infections / prevention & control*
  • Streptococcal Infections / transmission
  • Streptococcus agalactiae / isolation & purification
  • Vagina / microbiology


  • Ampicillin